Biometrics - Hand Geometry

One way to identify a person is to measure the unique geometry of their hand. This is an attractive biometric because it is minimally invasive and has no criminal stigma associated with it (unlike fingerprints). Feature extraction involves computing the widths and lengths of the fingers at various locations using the captured image. These metrics define the feature vector of the user's hand. Current research work involves identifying new features that would result in better discriminablity between two different hands, and designing a deformable model for the hand.

In our system the image acquisition system comprises of a light source, a camera, a single mirror and a flat surface (with five pegs on it). The user places his hand - palm facing downwards - on the flat surface of the device. The five pegs serve as control points for an appropriate placement of the right hand of the user. The device also has knobs to change the intensity of the light source and the focal length of the camera. The lone mirror projects the side-view of the user's hand onto the camera. The device is hooked to a PC with a GUI application which provides a live visual feedback of the top-view and the side-view of the hand. The GUI aids in capturing the hand image.

Geometric measurements of the human hand have been used for identity authentication in a number of commercial systems. Yet, there is not much open public literature addressing research issues underlying hand geometry­based identity authentication. This work is our attempt to draw attention to this important biometric by designing a prototype hand geometry­based identity authentication system. We also present our preliminary verification results based on hand measurements of 50 individuals captured over a period of time. The results are encouraging and we plan to address issues to improve the system performance.